Vibrating screen



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Marh 22 1927.

G. A. OVERSTROM VIBRATING SCREEN 1,621,949 G, A. ovt-:RsTRorvlv VIBRATING SCREEN March 22 1927.

Filed Sept. 28. 1920 3 Sheets-Sheet 2 l Ml:

- faz/en for l G. A. ovERsTRoM AVIBRATLNG SCREEN Filed Sept. 28. 1920 3 Sheets-Sheet 5 Patented Mar. -22, 1927.

'd UNITED STATES GUSTAVE A. OVERSTROM, 0F PASADENA, CALIFORNIA.

VIBBATING SCREEN.

Application led September 28, 1920. Serial No. 413,376.

My invention relates particularly to screens where a ver high frequency of vibration is employe to accomplish the desired results.

My object is to provide a vibrating-screen box, in which all of the screen is effective screening` surface, thereby using u the minimumoic screen cloth, and in which as many different sized products as may be desired can be made.

Another object is to provide the most simple and efficient flexible supporting means to this screen box, so as to allow of it being vibrated without transmitting the vibrationsto the structure on which the apparay tus is supported.

A further object is to provide a screening apparatus which is `practically noiseless. easy to erect and repair, andl which will produce no wrecking action on the screen cloth.

Another object is to provide an effective and simple vibrating means, capable of being driven by any available powerfat a high rate of speed, and which will even on a level, move the material forward. y

A still further object is to provide a vibrating screening apparatus `which is not sensitive to accidental overload, but which has a surplus of power available in case of need.

'Another object is to produce a combination of vibrating means, screen supports, and stretching means, that are extremely iiexible in their combinations and application thereby suiting any conditions that may be presented.

Other objects will appear in the specilication and description of, my invention.

In carrying out my invention I provide, generally stated, a vibrating screen box in which 'one or more screens are stretched tight. The box is supported on springs which are fastened to rigid supports. These springs allow of the frame being vibrated in a vertical plane. The vibrations are prov duced by the revolutions of a fast running unbalanced pulley, that revolves on a hollow shaft rigidly fastened to the screen box. Tlie pulley-has oil chambers at bothends. Qil. under strongcentrifugal pressure is circulated 'by means of stationary scoops,

'freie the revolving oil chamba@ t0 the 'wai ning surfaces, and back -to the'chambcrs agam.

The oil pressure thus produced, distributed over the whole eli'ective bearing surface,

is greater than the pressure produced by therevolving unbalanced pulley,thereby insuring a cool running and lasting oil floated bearing.

The lmaterial is advanced from the head A to the tail of the screen by the combination ot' the springsupports and the direction of revolution of the pulley, which must revolve in the same direction as the desired travel, looking down on the top of thepulley.

ln the drawings accompanying this specitication and forming a part thereof, Figure 1 is a plan view of one type of my vibrating screen. v

Figure 2 is a vertical longitudinal section taken on line 2., 2 of Fig. 1.

Fig. 3 is a side elevation.

I Fig. 4 is a transverse section on line 4, 4,

rinf. 3.

Fig. 5 is a transverse section on line 5, 5, Fig. 3, the pulley and shaft shown full view. 4

Fig. 6 is a section through the oil chamber on line 6, 6, Fig. 5.

Fig. 7 is a cross-section through the unbalanced parts of the pulley.

Fig. 8 is an enlarged end view of one of the springs which support the screen box and allow it to vibrate.

' Fig. 9 is a longitudinal section through the pulley, the shaft being shown full.

Fig. l() is a transverse section through the oil chamber on line 10, 10, Fig. 9.

Fig. l1 is a transverse section of the pulley on line 11, 11, Fig. 9, showing both the permanent and the adjustable unbalanced weight.

Figs. 12,13 and 14 illustrate a modified construction of pulleys in which the two Qil chambers have communication through the body of the pulley.

Fig. 15 is a longitudinalv section through a pulley and oil chambers usedon large and wlde screen boxes, illustrating also the weights placed 1'80 degrees apart.

Fig. 16 is a cross-section of a wide screen box in which the inside of the springs and the supporting pi es are stationary.

Figs. 17,18 an I 19 are diagrams to lllusv.

trate various methods of application, the letter A representing the finest size the letter F the coarsest and intervening letters the next size'in rotation.

Fig. 20 is a detail, showing a method of fastening line screen cloth to the stretching beams. Y

ig. 21 is a cross-section of a screen box illustrating various stretching methods embraced in my invention.

The same part is designated by the same reference sign.

In the operation of vibrating screens, I havefound that the longest life of the screen cloth, as well as the greatest capacity per square foot of screening surface and the least blinding of the screens is obtained when the screen cloth is stretched tight between tthe sides of a vibrating box, and

rigidly held tosuch box at the sides and ends only, allowing a clear unobstructed flow over the screening "surface without bolts, rivets or other obstructions to hold the screen cloth to the vibrating member, either longitudinally or crosswise of the screening surface. For example, I have tried the scheme of bolting the screen cloth to both longitudinal and cross beams placed in the screen box, but found that not alone did such bolts interfere with proper screening, but the screen cloth wires near the bolts crystallized and broke long before the rest of the screen cloth was Worn out. Steel beams used for this supporting purpose also crystallized and'broke vnear the bolt holes in a remarkably short time, but wood beams did not break, nor steel when reinforced by wood, or when rigidly held between wood frames. l

I found also that where the sides of the screen cloth were rigidly held to a stationary frame, and the central part of the wire screen cloth was attached to a vibrating member, that not alone did the wires soon break near the vibrating connection bolts, but the whole screen cloth Wore rapidly where the wires were in contact with each other. Undoubtedly this was caused by the mechanical wrecking action' and abrasion due to the distortion of the position of the wires.

I therefore naturally reached the conclusion that the wires comprising` the cloth must not be disturbed in yrelation to each other, but must move in unison throughout the width and length of the screen cloth, and that the screen cloth should not be fastened to the vibrating member anywhere on the screening surface. Longitudinal connections to the center of the screen cloth prevented the even distribution of the material to be screened, especially if the feed did notland exactly uniformly each side of such connections.

v11.1 my experience with vibrating screens,

inch size, the capacity is increased to some extent up to 3300 vibrations per minute, and on fine dust even up to 4000 er minute, but beyond i500 per minute, t e capacity rather falls down. possibly due t0 that gravity has not time to move the particles suiiicien'tly downward through the meshes, before they are again thrown upward by the wires.

As a general rule, I operatemy screens from 2500 to 3000 vibrations per minute, and the vibrations may be about ,1g-inch diameter on fine material, 1/8. on medium size and f or slightly over on coarse as well 'as on moist material, on which less number of vibrations and greater movement gives better results.

I have built the type of screen here shown in sizes from 1 ft. wide and 4 ft. long up to as large as 4: ft.Y Wide and 16 ft. long making as many as 7 sizes of products in one box, and it can be readily understood that to vibrate a screen of this latter size at the rates given, with at times as much as 1200 lbs. of a movin" load on the screen, is a serious problem, and can not be done without. an unusual operating mechanism, and for this I employ an unbalanced pulley of a special design to assure cool running. I have found that any ordinary bearing inside of 10 minutes run, under the severe conditions mentioned, will be' smoking hot and melt babbitt, whereas with the construction shown, the pulley has run cool for over 200 hours, without replenishing the oil in the pulley.

I have found the most etlicient vibratory motion for screening to be'a concentric or only slightly elliptic motion in ar vertical plane.

In order to save valuable mill height, the motion should be differential or have a decided tendency to move the material forward from the head or feed end to the tail or discharge end of the screen. This allows the use of less pitch or incline to the screen, than if only gravity is depended upon to move the material forward. On very accurate screening my vibrating screen can beoperated on a level, or eveiL up hill. vT he screening is more rapid when the material moves in a thin stream over the surface than out the flow, but in such a case the gravity loses its screening ability as it is 11sedup in transporting the material.

Contrary to popular opinion, it is gravity and not the vibrations that accomplish 4the screening. The vibrations keep the oversize Jumping up out of the way and clear the meshes, allowing the undersize to drop through the meshes from the force of gravity.

I have observed that when a screen is overloaded, it may not actually screen through the meshes one-quarter as much material as when loaded slightly Abelow capacity. The cause islsimple; the overload gives a deep bed of material through which the vibrations are not able to drive the oversize, some of which may stay still, in the meshes, so that the undersize cannot drop through, hence the whole mass may slide down without bein screened. Especially, is this true when tluandling an overload of moist and sticky material.

^ From experience, I have ,found that it is necessary` to provied a surplus of available power with correspondino' resistance in a vibrating screen, so that, in the feed supply (due to a temporary choke or other accident) the power is strong enough to vibrate this overload.

By the use of more weight in the pulley and stiffer resistance springs than ordinarily are required to handle the usual load, the overload is taken care of without using up but little more power than if just the'right weightin pulley with correspondingly weaker springs were used to barely handle the regular load.

' It naturally takes power to keep .the oversize n constantsuspension, and on the move, hence the larger tonna e handled, the more power is. required. ut the unbalanced weight tries to revolve around its center of gravity against what vresistance it meets, hence if only small 'spring ,resistance were provided, the vibrations would be greater when underloaded or running idle, than when loaded to capacity or overloaded. Therefore, the vibrations must be of nearly same amplitude under all conditions of load; Otherwise, they would become destructive to the life of the apparatus when underloaded and impotent when overloaded.

The screen box is made up of the sides 1, to which are attached the top rails 2, and bottom rails 3, the head end 4, the tail end ties 5 and 6, the tie rods 7, the pipe struts S and the strut 9. Bolts 10which pass clean through the bottom rail, 3, sides 1 and top 'rails 2, serve to hold down pipe clamp 1L to the top rails 2; clamped fast in the pipe clamps 11 are supporting pipes 12 which have collars 13 shrunken. To the ends, of pipe 12 are pressed on the spiral springs 14, which are held in place, by check nuts 15,

if any sudden rush on the extreme end of ipes 12'. The spiral springs14 are clamped fast in the spring clamps 16 which are held rigidly by bolts 17 to the stationary supporting beams 18. It is immaterial if the exact order of fastening as here outlined is employed or if, as is done in the largest screens, shown in Fig. 16, the spring clamp casting is bolted to the top rails 2 and the pipe clampsll are bolted to the supporting beams. 18, in which case the pipes 12 are stationary and the outside of springs 14 vibrate with the screen. `As shown in Figures '1, 2, 3 and 4, the outsides of the springs 14 are stationary and the insides of the .springs 14 and the pipes 12 vibrate with the screen. screens also, I. usually provide a double set of springs to support the greater weight and still use same size springs with a large size'A pulley, indicated in Fig. 19. The only reason for using pipes in place of solid rods is that the rods are more liable t'o crystallize and break than are pipes, and, especially on very wide screens, it would be impractical to use long rods that vibrated with the screen box.

Bolts 19 pass clean through the rails and sides of screen box and serve' to hold down shaft clamp 20 to the top rail 2. This clamp is placed a little nearer to the head end than to the tailend of the screen box, so as to give the head end a greater effort than the tail end, because the load to be screened is greatest at the head end and besides the feed needs more violent shaking in the beginning than later on, yso as to stratify the finer material as soon as possible yto the bottom of the mass to be screened. A hollow shaft 21 is clamped fast in shaft clamp 20. Plugs.

22 serve to close u the ends of the hole 23 in the shaft 21. ear the end of the' shaft is fastened a pipe nipple 24 that communicates with the hole 23. On the end of the nipple is a stop cock 25, screwed on. The upper end of the stop cock is plugged with a removable plug 26.

From the outside of the shaft and communicating with hole 23, are drilled oil holes 27, 28. and 29.

0n the surface of the enlarged part of the shaft are oil grooves 30 cut right 'and left hand as shown in Fig. 9 and Fig. 15where two oil scoops are used, or only right hand as in Fig. 12, where only one oil scoop 1s used.

On the shaft 21 is mounted an unbalanced pulley 31, having an anti-friction bush1ng`32 ressedvinto' the hub of the pulley. This ushing has a free running fit on the shaft 21. The pulley has a crown face 33 in the center to receive the belt drive` and flanges 34 on the ends. which form one side of the oil chambers 35, and also a pocket 36 in which weights 37 may be' fastened, as for example with setscrew 38 and check nut In the larger.

39 pushing the weight 37 up against pins 40. Caps 41 which are threaded on to the flanged part of the pulley complete the oil chambers 35. Gaskets 42 prevent oil leakage past the threads. In the hubs 43 of caps 41 are felt rings 44 to prevent dust and grit from entering the oil chambers. In the event that more oil has been put into the chambers than is necessary,.these felt rings also prevent the oil from leaking out from the oil chambers when the screen is standing still On the shaft 21 and enclosed inside the oil chambers 35 are fastened oil scoops 45, which communicate with the hole 23 by means of oil holes 27.

It is not necessary to use two oil scoops but only one serves the purpose fully as well, in the smaller size screens, and would be just as well in the larger pulleys also. The diameter of the pulley is limited by the limit of belt speed, therefore, in some cases there is not room enough to make an oil return through the body of the pulley from the one oil chamber to the other, which is necessary-where only one oil scoop is used.

In Fig. 12 is shown the oil scoop 45 in the right hand chamber and in the left hand chamber is shown a set collar 46 to limit the end play of the pulley. Return holes 47 through the body of the pulley put the two chambers in communication with each other, so that the oil which comes into the left hand chamber can return to the 'right hand chamber to be again picked up by the scoop.

. In Fig. 13 the bushing 32 contains the holes 47. and the bushing is made out of balance in place of the body of the pulley.

In Fig. 14, the holes 47 are in the body of the pulley, there being no holes for a distance of about 120 degrees, thereby making the pulley out of balance.

In Fig. 9 and Fig. 15, where two oil scoops are used. it is necessary that there is communication also between the two oil chambers, but here the communication is throu h the hollow shaftby means of hole 23. y means of this connection, the centrifugal oil level indicated by line 48, Fig. 10, remains in balance. If there is more oil going back to one chamber than t0 the other, the centrifugal oil level will rise in that chamber, and consequently the oil pressure in that scoop is greater than in the opposite scoop, which will then cease to pick up oil until centrifugal levels in both chambers are a 1 re.

When the construction shown in Figs. 12, 13 and 14, is used` the centrifugal oil level in the left hand chamber must of necessity rise tothe return holes 47 and the centrifugal levels are not alike at both ends unless there is oil enough to lill both chambers up to the return grooves. However, as a rule, only about enough oil is put in to fill the chambers to the level line 49 (see Fig. 10), which indicates the oil level in both chambers when pulley is not revolving and this amount of oil will form centrifugal levels 48 when'pulley revolves. The line 49 is just below the shaft, and if chambers are only filled to that level, there can be no oil leakage when pulley is standing still, nor can there be any oil leakage whenpulley is running even if filled beyond level line 49. If oil'enough is put in to merely ill the chambers, some oil will fiow down the outside of the scoops to the shaft and the felt rings, and a slight oil leakage will continue until surplus oil is eliminated. Undoubtedly there is some splash over the scoops that even at the lesser levels will reach the shaft and felt rings. and to prevent anyl leakage from that source, holes 5() connect the bottom of the felt grooves with the oil chamber.

The construction shown in'Fig. 15,- which is used on the. wide screens, has three bearings.

The center bearing is necessary to prevent heating of the end bearings. When only end bearings are used,` the shaft evidently bends slightly under the vibrations unlessl it were made larger than is practical, but the pulley structure being practically of pipe construction and of larger diameter, bends but slightly, hence there is a binding in the end bearings and they become very hot, but as arule only one of them at a time. One day the left hand bearing may run hot, and next day or hour it may cool down and tl1eother run hot, and the cause for this erratic behavior I have been unable to discover. By putting in the center bearing and compelling both the pulley and shaft to bend together, (if bend there is) the heating trouble is eliminated. The-belt pull always being upward and the bending of the shaft naturally downward, more than in any other direction, also served to agvravate the heating of the end bearings, before the center bearing was introduced. With the single bearing construction and oil scoops as shown in Figures 9 and 12, no hot bearings develop. In the construction shown in Fig. 12, the scoop end of the pulley is slightly warmer than the other end, and the construction shown in Fig. 9, develops slightly more heat than as in Fig. 12 and is evid-entl caused by the extra friction between the o1l 4and the second oil scoop.

I aim to proportion the pulley design s0 that the pressure per square inch of the oil (which by actual gauge test on medium size pulley has been shown to be 25 lbs. per square inh, when running 2500 rev. per min.) multiplied by the projected bearing, surface in square inches, will be considerably larger than the pounds centrifugal force developed by the unbalanced revolving weight in the pulley. Thus the oil pressure vkeeps lthe metal surfaces of the bearings away pose of conveying any grit or dirt that may e present in thevoil or worn ofi' from the bushing, so that the bearing will not be scored. Any grit that leaves the center bear-` ing is caught in the cooling chambers 51 formed between the center bushing 32 and the end bushin s 32, and held by centrifugal force to t e outside of this chamber, thereby preventing the grit from entering the end bearings.

On account of being assured of clean oil for these' bearings,l oil holes 29 are not needed, nor-desirable. The oil is cooler in the cooling chambers 51 than in the oil chambers 35, which are fed with oil coming directly from the end bearings, where most heat is produced. Some heat is also produced by oil friction against the outside of the oil scoops in chamber 35. It will,

' therefore, lbe seen that oil should not be taken directly fromA the oil chambers 35 to the end bearings, but first through the cooling chambers. The oil lpressure from the scoops and centrifugal force combined fill up the coolin chamber completely with oil, distributing t e. oil to all parts of the end bearing surfaces uniformly and gives better results than if the oil Acame out of holes in these bearings. As the shafts for large wide screens must of necessity be llarger in diameter than for small and narrow screens, and still the pulleys must run at same speed ineither case, it will be understood that the olin system in the former must be still more pe ect than in the latter.

In the one bearing pulleys the bushing -32 may be made in two pieces each somewhat less in length than half of the. one full length bushing, thereby forming a chamber between the two, but the chambers would be so short that its practical value would be of smallconsequence.

' In the construction shown in Fig. 13, it is impractical to make the bushing in two pieces, as the danger of the counter-weights not lining up perfectly would be too great.

It is necessary that the weights in the pulley be either exactly in line at both ends of the pulley or else placed exactly 180 de-v grees apart. In the narrow screens the weights are always in line; in the very wi de screens, the weights in `one end may be exactly 180 degrees apart from the weight in the other end, so that one end always moves 180 degrees behind the other. In the very wide screens the center of the screen cloth in spite of thestretchinv will vibrate further than the sides where the screen cloth is held to the vibrating box, and by putting the weights at 180 degrees apart in such a case the vibrations of the screen cloth may be made almost alike all over, for the reason that when Weights are placed 180 de ees apart, the movement ot the lon itu inal center of the box is almost nil, but t e longitudinal center of screen cloth under uniform motion will vibrate more than the sides.

When using the construction here. described, there is no detrimental wrecking action produced on the wires from the 180 degree movement, because wires move with the box, and all parts of the wires are in the same ystill relation toward each other,

and are not being distorted.

On narrow screens, it is detrimental to the screen action to have the movement 180 degrees apart, as the longitudinal center becomes inert. K

The direction of the revolution of the pulley must be against the mouth of the oil scoop and, upper side of4 the pulley must revolve toward vthe tail end of the screen box, vas shown by arrows in the drawings.

The movement thus produced by the pulleys is lifting of the material on the head end and ythrowing it forward toward the tail end as this end drops. By actual trials, it has been demonstrated that when the pulley is 'revolved the other way (by turning 1 shaft and all end for end) much of the Inaterial will pile upy at the head end of the.

screen and actually travel back over the head board, even though the screen stands on an an le of 1 vertical to 2 horizontal.

hen a card is taken of the motion, `it

Vis found that the motion of the screen box screen box and allow it to vibrate with practically a concentric motion, are made sothat the inner end bears for about 1/3 of a turn on the second loop and the outer end bears for about 1A; turn on next to the last loop.

yThe springs may be welded together where the loops come in contact, but this is usually not necessary except with the outside end, when the springs are mounted as shown in 'Fig 1G, where the motion of the screen box is applied on the outside of the springs, in which case there is a slight tendency to movement on the outside loop, which is entirely prevented by ywelding before the springs are tempered. The inside loop is so stiff that no movement between the contact surfaces can be detected there, hence welding there except in very large springs, Vis of doubtful value. Both the inside and outside ends are tapered in thickness, but not Ain width, thereby producingv an even outside and inside surface. The hole or inside is concentric with the outside. The inside of the spring fits tightly on the supporting pipes 12, so that no movement or wear takes place there, nor is there any wear on the outside, which clamps fast in clamp castings 1'6. y i

These springs are admirably adapted to accommodate a concentric movement. They are noiseless in action, no 'lubrication is needed or desirable;V there is no wear or movement between the springs and their contacts. The'movement is all in the internal loops of the springs. No adjustments are needed to produce the required resistance. There is no chance for the operator to alter its function and thereby make the screen inoperative. It requires the simplest4 kind of fasteningonly. The stationary. supporting beams 18 may be placed fbelow the, supporting pipes 12 as shown in F' 4 and 5, or above as shown in dotted line 7, Fig.

V 4 and in Fig. 16.

The screen cloth 52 is fastened to stretching beams 53. .Stretching bolts v54. serve to draw the beams 53 toward the sides 1 or bottom rail 3, thereby pulling the screen cloth drum tight.

' In case where `wood is desirable for stretching beams, the construction shown in Fig. 4 is used. The edges of the screen cloth are turned at right angles and the cloth held Abetween cleats 55 and stretching beams 53,

the cleats being screwed on to the beams, thereby clamping the cloth between the two. The turned sides of the cloth are also tacked tf1) sltretching beams 53 in case of the finerl c ot A For stretching coarser and heavier cloth, steel` channels and angles are more frequently used, as shown in Fig. 16 and in more details in Figures v2() and 21 which show several variations, as for example, in-

dependent stretching at upper left hand and lower-right hand, or twin stretching at lower left hand and upper right hand, all in Fig. 21. In case of independent stretching with angles spacers 56 are used. When channels are used, they in themselves form spacers.

Inside liners 57 serve to protect the sides 1 from wear, and also to hold down solidly the stretching beams 53 to the bottom rails 3. The wedges 58 which bear against the top rails 2, serve to press down the liners 57. The wedges are' not driven home solidly' until the screen'cloth is stretched.

When heavy screencloth is used, it is only necessary to bend the sides of the cloth 'over double or lhshaped, then slip the U over This method ei'ectually prevents stretching beams from the screen box. In

case of very fine bronze and brass screens, I sometimes onl use the inside lU clip and solder screen clbth 52 to the inside U clip 59 as shown at 61,- Fig. 2.

Where twin stretching is used in triple deck screens with sizes in tandem'or more as shown in diagram, Fig. 1, the cloths cannot be slipped in when stretching beams are in position, but the screens must be put on to the beams outside the box and then dropped in lace. In that case a nut 62 is riveted or we ded to beams 53 and a tap bolt 63 employed for stretching. It would be impossible to put in bolts 54 in such a situation.

In operation, the pulley is belted to any convenient revolving power source and l speeded to revolve about 2500 or 3000 rev.

er min. in the direction shown by arrow.

t does not matter at whatangle the belt comes to the ulley providing it clears the screen box. he material to be screened enters at the head end, of Figures 1-2 and 3). a rule it does not pay to attempt to spread the feed perfectly uniformly all over at the head end by means of mechanical feeders, Ias an ordinary spreading box and a foot extra length of screen serves the same pur se, as the feed almost immediately sprea s over the full width of the screen, to uniform thickness:

Large enough weights 37 are added to give the desired' intensity of vibration. Before starting enough light oil is put in through the stop cock to fill the oil chambers to level line 49 which level can be determined b inserting a wire on the underside of sha l21 and between felts 44; when the oil comes out alongside the wire, the chambers haveenough. The wire then of course is removed. .f If it is desired to oil up while running, it is necessary to see thatstop cock 25 is closed, then remove plug 26, and in its place screw in an oil gun, then open the stop cock and force the oil down; close the stop cock, remove the o11 gun and replace the plug to keep sand out of the neck of the stop cock. If jlilug is removed and stop cock opened whl e running the oil will uirt upto a great height and be lost in asilew seconds.

There are no other adjustments except adding the proper size weights 37, and no other tie right hand end precautions exce t regarding the oiling' The machine gives a strong and intense vibration that screens materials at a very fast rate and the vibrations are not diminished by an overload. The pulley maintains a running heat of about 100 to 150 degrees Fahrenheit.

Wet or dry screening can be handled,

meshes do not clog and the machine requires j no attention except oil once a week.

Many -variations and changes in the details of construction and arrangement would readily occur to persons skilled in the art and still fall within the spirit and scope of my invention. I do not, therefore, desire to belimited or restricted to theexact details shown and described.

Having set forth the object and nature of my invention and various constructions embodyihg the principles thereof, what I claim as new and vuseful `and of my own invention and desire to secure by LettersPatent, is: 1. In a vibrating screen structure, a screen adapted to support the material to be screened, coiled supporting springs for said screen, said springcoils disposed in a plane vertical to theV screen surface, the whole weight of the screen being imposed on said coiled springs in a direction transverse to the axes of the coils thereof, and an unbalanced revolving member wholly and freely mounted to said screen to vibrate the same in vertical planes.

2. In avibrating screen structure, a

screen, a stationary supporting frame, transverse screen supporting members for said screen, coiled springs on said members disposed between the same and the stationary supporting frame, the coils of said spring being disposedin a planel vertical to the screen surface, said spring coils being arranged to supportV the whole Weight of the scr en in a direction transverse to the axes of the spring coils thereof, and means Wholmounted on and carried by the screen to ipate the same in 4vertical planes.

a. In a vibrating screen structure, l a screen, a stationary supporting frame` transverse members for said screen extending to said frame, involutely coiled springs on/'said members, the coils of said spring being disposed in a plane vertical to the screenl surface, said spring coils being arranged to support the whole Weight of the screen in a direction transverse to the axes of the spring .fcoils thereof, and means mounted freely on and carried b`yf the screen'to vibrate said screen in planes vertical to said spring coils.

4. In a vibrating screen, a screen element, a stationary element, supporting shafts disposed transversely with respect to said screen and stationary elements, and carried by one of said elements, coiled springs mounted on said shafts and interposed between said shafts and the other of said elements, said spring coils being adapted to vibrate in planes vertical to the plane of the screen element, and means wholly and freely mounted on the screen to vibrate'flsaid screen in vertical planes. f 5. In a vibrating structure, a] vibratory element, a bearing shaft mounted on said element to vibrate with said element, a revolving pulley mounted on said shaft, an oil chamber, an oil scoop' arranofed; therein, one of these members mounted to rotate with said pulle an oil passage from the oil scoops'to the earings of said pulley, 'and means to return the oil from the pulley bearings to the chamber.

6. In a vibrator structure, a v ibratory element, a rotatable unbalanced element having vbearings carried` by the vibratory element, an oil chamber carried by one of said elements, means mounted within said chamber and carried by the other of said elements, and communicating with the bearings'for said rotatable unbalanced element to distribute oil from said chamber to said bearings, and means to cause the return of the sed oil from said bearing to said cham- 7. In a vibrator structure, a vibratory element, a rotatable unbalanced element having bearings, an oil chamber carried by one of said elements, oil delivery means mounted Within said chamber and carried by the other of said elements, said chamber and said oil delivery means respectively communicating with said bearings, and means to maintain pressure within said chamber and bearings.

8. In a vibrator structure, a vibratory element, a shaft, bearings therefor, said bearings carried by said vibratory element, a rotary member carried by said shaft, an oil chamber carried by said member and communicating with the said bearings, and means whereby the centrifugal pressure on the oil produced by the rotation of lsaid chamber delivers the oil from said chamber to the shaft bearings, and means to rotate said member.

9. In a vibrator structure, a vibratory element, a shaft carried thereby, and fixed rigidly thereto, a pulley device mounted to rotate upon said shaft, an oil chamber mounted to rotate with said pulley, means for 'distributing a lubricant mounted `on said shaft and disposed'within said chamber and communicating with the bearing said pulley. y 10. In a vibrator structure, a vibratory element, a shaft carried thereby, and fixed rigi-dly thereto, a pulleyudeyice mounted to rotate upon said shaft, an oil chamber moun ed to rotate with said pulley, means surface of said pulley, land means to rotate l for distributingx a lubricant mounted on said y shaft fand' disposed within said chamber and communicating With the bearing surface of said pulley, means to return the excess oil from said`bearing surface to said chamber, and means to rotate said pulley.

.. 11. In a lvibrator structure, a vibratory element, a stationary frame, shafts disposed adjacent eachy end of said vibratory element. and extending transversely thereacross, and supported vby said stationary frame, coiled springs mounted upon said shafts in a plane vertical to the surface of said vibratory element and forming a yielding suspension for said vibratory. element, apulley journaled upon the vibratory element and. extending .transversely thereacross, means to rotate said pulley, and means. actuated by the rol5 tations of said pulley for supplyin a lubricant to the bearing surface thereo 12. In a screen structure, a. vibrating screen having supportin journals for its Whole Weight, coiled springs on said journals having axes disposed transversely of the screen, said screen being suspended upon said spring coils, and means supported freely l on the screen` to cause said screen to vibrate in a plane at right angles to the plane of 25 ,the screen.

GUSTAVE A, OVERSTROM. 

